Prosthetic device

ABSTRACT

A prosthesis that resiliently engages a body passage includes an annular clamping ring which may be folded along a diametric axis for insertion into the body passage. The clamping ring is adapted to resiliently spring outwardly, once in position inside the body passage, and to be continually resiliently biased against the interior surface of the body passage. One or more of the clamping rings may be attached to opposed ends of a tubular graft. The rings and connected graft may be positioned in the body passage using an applicator which selectively permits expansion and/or in some embodiments contraction of the annular ring in position within a body passage. Alternatively a retaining member may be used to retain the annular ring in a compressed condition until it is in a desired position within a body passage. Among other potential uses, the present invention may be useful as a vascular stent for treating abdominal aortic aneurysms.

This is a continuation of prior application Ser. No. 08/878,908 filed onJun. 19, 1997.

BACKGROUND OF THE INVENTION

The present invention relates to devices that are retained inside a bodypassage and in one particular application to vascular stents for therepair of arterial dilations known as aneurysms.

As a result of arteriosclerosis, portions of blood vessels may becomeweakened and extremely dilated. These dilated vessels may be treated bybridging the dilation or weakened extended area using a vascular tubularprosthesis. In this way the diseased portion of the vessel iseffectively isolated from the pressure inside blood vessels.

Vascular tubular prostheses may be inserted into the diseased portion ofthe vessel by surgically opening the vessel and suturing the prosthesisinto position. However, it may be preferred to insert the prosthesisfrom a remote opening, such as the femoral artery, adjacent the groin,using a catheter system. This is because the elimination of the need toopen a major body cavity may diminish the potential surgicalcomplications.

Generally it is desirable to insert the prosthesis, using a catheter, ina collapsed or compressed condition and then to expand the prosthesiswhen in position. One reason for this is that it is desirable to avoidsubstantially occluding the blood flow during the insertion process.Therefore, by collapsing the prosthesis, the prosthesis may be readilypositioned inside the vessel, in some cases without substantiallyoccluding the blood flow.

There are generally two techniques for expanding the prosthesis once itis in position at the location to be repaired. One technique uses amalleable metal prosthesis which has two configurations. Oneconfiguration has a relatively smaller diameter and the other has arelatively radially expanded configuration contacting and securing to aneck portion on either side of the diseased vessel region. Theprosthesis may be a malleable metal ring which may be expanded by aballoon catheter to set the prosthesis in its expanded diameter, insidethe neck portion, proximate to the diseased portion of the vessel.

Another general approach is to use a self-expandable prosthesis whichmay be compressed against a resilient bias. Once in position, theprosthesis is allowed to resiliently expand into contact with the vesselwall.

While a wide variety of solutions have been proposed to the problem ofeffectively bypassing diseased tissue, various existing prostheticdevice designs may have certain deficiencies. For example, in somecases, the neck portion on either side of the diseased vessel portionmay be relatively short. This makes it difficult for prosthetic devicesto adequately engage the narrow neck on either side of the aneurysm.

In addition, some of the existing prostheses may cause blockage of theblood flow during insertion, which can have physiologically adverseaffects. Still another issue is that many existing prostheses do notadequately seal against the internal surface of a vessel, allowingleakage of blood past the prosthesis into the region between theprosthesis and the weakened blood vessel. The consequences of this typeof leakage can be traumatic. In some designs, the device may not beadaptable to non-circular or irregularly shaped neck regions.

Still another issue with some known prostheses is that they may requirethe hospital to stock a variety of prosthesis sizes for differentsituations and different patient physiologies. Also some designs mayrequire that the prosthesis be custom fitted for each particularpatient.

Another difficulty may arise with regard to accurately positioning theprosthesis once it has been expanded. In some cases inaccuratepositioning may be problematic. Similarly, many existing prostheses maybe dislodged from their desired position so that they do not effectivelyaccomplish the function of protecting a weakened vessel.

Thus, for these and other reasons, there is a continuing need forenhanced solutions to the problem of repairing diseased vessels and ingeneral to the problem of effectively securing prosthetic devices to theinternal walls of body passages.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a device for retaininga prosthesis in a body passage includes an annular, resilient element.The element has an undeformed diameter greater than the diameter of thebody passage.

According to another aspect of the present invention, a prosthesis forinsertion into a body passage includes an annular, resilient springelement and a tubular graft. The graft may be attached to the element.The element has an undeformed diameter greater than the diameter of thegraft.

According to still another aspect of the present invention, a vascularprosthesis for repairing a diseased first vessel includes a resilient,annular ring having a first pair of loops extending in one direction,and a second pair of loops, extending in the opposite direction. Thefirst and second pairs of loops are connected together. A tubular graftis connected to the ring. The graft is arranged to extend along thelength of the first vessel and the first pair of loops are arranged toextend at least partially past the point where a second vesselintersects the first vessel. One of the second pair of loops defines anopening to permit communication between the first and second vessels, atleast partially past the prosthesis.

According to yet another aspect of the present invention, a method ofsecuring a prosthetic device in a body passage includes the step offolding a resilient annular ring to assume a first configuration havinga cross-sectional area smaller than the cross-sectional area of theundeformed ring. The ring is positioned at a desired location within abody passage and allowed to resiliently deform to a secondconfiguration, having a larger diameter than the first configuration,but still having a cross-sectional area smaller than that of theundeformed ring.

According to but another aspect of the present invention, a method forrepairing a diseased vessel includes the step of folding an annular ringon its diametric axis to assume a smaller cross-sectional configurationand forming a pair of loops extending away from the axis. The ring isarranged in the vessel with its diametric axis proximate to anintersecting vessel such that the loops extend at least partially pastthe intersecting vessel without occluding the intersecting vessel.

According to yet another aspect of the present invention, a method forsecuring a prosthetic device inside a body passage includes the step ofdeforming an annular resilient spring by folding said spring along itsdiametric axis. The spring is positioned inside a body passage. Thespring expands resiliently against the body passage. The springcontinuously presses outwardly against the body passage.

According to but another aspect of the present invention, a prostheticdevice includes a prosthetic heart valve, a flexible tubular sleevehaving a first end connectable to the valve and a second end. Adeformable, resilient annular ring is connected to the second end andarranged to connect the graft to the interior surface of a portion ofthe ascending aorta.

According to yet another aspect of the present invention, a prosthesisfor insertion into a body passage includes at least two annularresilient spring elements and a flexible, tubular graft attached to eachof the elements. A rigid member longitudinally connects the elements.The rigid member is less flexible than the graft.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a generalized top plan view of a clamping ring in accordancewith one embodiment of the present invention;

FIG. 2 is a reduced, perspective view of the embodiment of FIG. 1 inplace within an idealized body passage;

FIG. 3 is a front elevational view of a clamping ring before insertioninto a body passage;

FIG. 4 is a front elevational view of a clamping ring after introductioninto a body passage;

FIG. 5 is a side elevational view of the embodiment shown in FIG. 4;

FIG. 6 is a front elevational view of a prosthesis with an applicationapparatus;

FIG. 7 is a cross-sectional view taken generally along the line 7—7 inFIG. 6;

FIG. 8 is an enlarged, partially sectioned view of the retention deviceshown in FIG. 6;

FIG. 9 is a cross-sectional view taken generally along line 9—9 in FIG.8;

FIG. 10 is a cross-sectional view taken generally along line 10—10 inFIG. 8;

FIG. 11 is an enlarged front elevational view of a prosthesis retainedby a retention loop;

FIG. 12 is an enlarged, front elevational view of a portion of theretention loop;

FIG. 13 is a front elevational view of another embodiment of theprosthesis and insertion device;

FIG. 14 is an enlarged view of the prosthesis shown in FIG. 13;

FIG. 15 is an enlarged cross-sectional view of the embodiment shown inFIG. 11 prior to insertion into a body passage;

FIG. 16 is a cross-sectional view of the embodiment shown in FIG. 13prior to insertion into a body passage;

FIG. 17 is a front elevational view of another embodiment in placewithin a sectioned aortic bifurcation;

FIG. 18 is a front elevational view of still another embodiment in placewithin a sectioned aortic bifurcation;

FIG. 19 is an enlarged front elevational view of a module shown in FIG.18;

FIG. 20 is a cross-sectional view taken generally along the line 20—20in FIG. 19;

FIG. 21 is a cross-sectional view taken generally along the line 21—21in FIG. 19;

FIG. 22 is a front elevational view corresponding to FIG. 14 showing analternate embodiment;

FIG. 23 is a partially sectioned front elevational view of anotherembodiment; and

FIG. 24 is a front elevational view of a prosthetic device positionedwithin a sectioned heart.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring to the drawing wherein like reference characters are used forlike parts throughout the several views, an annular, resilient clampingring 30 may be formed of a plurality of strands 32 of resilient wire asshown in FIGS. 1, 8 and 10. One embodiment of the ring 30 may be formedby wrapping a single length of wire around the mandrel (not shown)having a central axis “C” and then securing the strands into a bundleusing ties 34. The ties 34 may be formed from surgical suture material.Of course, the ring 30 may be formed by a variety of other techniquesincluding the use of a single strand of wire, the use of multiplestrands of helically intertwined wire, as in multi-strand wire rope, orany other suitable technique which forms a highly resilient annularring.

The number of coils or strands 32 can be varied according to the wireutilized and the particular application involved. However, in oneembodiment, the number of strands 32 utilized is approximately 8 to 10as shown in FIG. 10. However, the number of coils or strands 32 may varyfrom as few as 2 to as many as 100 or possibly more.

While a variety of different wire diameters may be utilized, theindividual strands 32 may have a diameter of from about 0.05 to 1 mm. Inone advantageous embodiment a wire strand 32 diameter of about 0.1 mmmay be used.

The strands 32 may be made of any highly resilient metal or plasticmaterial, including a nickel titanium alloy such as Nitinol. Generallythe resilient or superelastic or martensitic form of Nitinol isutilized.

The diameter D_(K) of the ring 30 is subject to considerable variationdepending on the particular body passage involved. In connection with anaortic vascular graft, a ring diameter of about 30 mm may be adequateand in other situations ring diameters (D_(K))of from about 6 to 50 mmmay be suitable.

Referring to FIG. 1, the ring 30, before compression, may have adiameter, D_(K), which is considerably greater than the diameter, D_(R),of the body passage 36 to be treated. As indicated in FIG. 1, twodiametrically opposed points “A ” on the undeformed ring 30 may bedeflected towards one another. As indicated by the arrows, this causesthe ring 30 to fold along its diametric axis “B”. In this configuration,the ring 30 may be inserted into the body passage 36 in a reducedcross-sectional configuration.

As a result of the folding along the diametric axis “B,” the loops 38,which include the folded tips “A,” extend proximally relative to thepoints “B” which are along the diametric axis of folding. As usedherein, the term “proximal” refers to the direction upstream withrespect to blood flow and the term “distal” refers to the directiondownstream with respect to blood flow.

Once in position inside the body passage 36, the ring 30 makescontinuous contact with the internal vessel 36 wall even though the ring30 may take a generally sinusoidal shape. To a first approximation, theheight H, indicated in FIG. 2, is a quadratic function of the radialcompression.

The smallest permissible bending diameter without plastic deformation,D_(B), shown in FIG. 2, depends on the material, the thickness of theclamping ring 30 and the individual strands 32 which may make up thering 30. According to Hooke's law, the strands 32 can be regarded asparallelly connected springs whose deflection characteristic values areadditive and whose individual low radial tension forces add up to atotal tension force which depends on the number of strands 32. When theentire ring 30 is compressed, each individual strand 32 has a bendingdiameter approximately corresponding to the minimum bending diameterD_(B) of the individual strand 32.

As an approximation, the minimum bending diameter D_(B) is approximatelyten times the wire diameter. This suggests that the ring 30 wirediameter be kept low. However, the ring's clamping force on the bodypassage 36 is a function of its diameter, suggesting conversely that thewire diameter be increased. This tradeoff can be optimized by using aplurality of strands 32, whose diameter controls the minimum bendingdiameter, to form a bundle whose composite diameter controls theclamping force. Thus a clamping ring 30 with a high tension force can beshaped to a relatively small compressed configuration. After beingreleased from a catheter, for example having a conventional diameter offrom 4 to 6 mm, the ring 30 may return to its original shape and bymeans of sufficient tension force, securely presses the ring 30 alongthe wall of a body passage 36.

A prosthesis 40 may include an annular ring 30 and a graft 42, as shownin FIG. 3. The graft 42 may be generally tubular and made of a fabric orfilm secured on one end to the ring 30. The graft 42 may have a diameterD_(P) which is smaller than the diameter D_(K) of the clamping ring 30.Due to the connection between the clamping ring 30 and the end of thegraft 42, there is a diameter D_(KP) at the junction point between theclamping ring and the graft 42. The clamping ring 30 may expand the endof the tubular graft 42 to a stop or deformation limit, after which nofurther expansion occurs. Thus, the ring 30 may expand upon the graft 42in the region proximate to the ring 30 so that the diameter of the graft42 gradually tapers in the region 44 down to a relatively constantdiameter region 46, terminating in a free end 47. Alternatively, thegraft 42 could be preformed in the flared shaped shown in FIG. 3.

Any one of a variety of fabric materials compatible with humanimplantation may be utilized to form the graft 42. For example, thegraft 42 may be formed of flexible woven or knitted textiles made ofDacron, Teflon, or other materials. It is advantageous if the tubulargraft 42 is made of a material which does not change its circumferencereadily. It is also advantageous if the portion 46 of the graft 42 has adiameter D_(P) which is approximately the same as the diameter D_(R) ofthe body passage 36 to be repaired.

The ring 30 can be connected with the region 44 by means of sutures orbonding. It is advantageous if the clamping ring 30 is arranged on theinterior surface of the graft 42 so that when the ring 30 extendsagainst the body passage 36 wall, the graft 42 intervenes between thepassage 36 and the ring 30. Thus, it may be advantageous that thediameter D_(K) of the ring 30 be considerably greater than the diameterof the portion 46 of the graft 42.

Referring to FIG. 4, the prosthesis 40 may be positioned within theabdominal aorta 48 proximate to the left renal artery 50 and the rightrenal artery 52. The loops 38 extend past the arteries 50 and 52 whilethe portion 53 is located just distally of the openings to the arteries50 and 52. Thus, as shown in FIG. 5, the openings to the arteries 50 and52 are not in any way occluded by the positioning of the annular ring 30proximate thereto because of the generally C-shaped configuration incross-section of the ring 30.

Because of this configuration, the ring 30 may be secured to asubstantially undeformed neck region 54 of relatively short heightbounding an aneurysm 55. This is because at least part of the ring 30extends proximally beyond the neck 54 without in any way affecting theflow through the arteries 50 and 52. Moreover, because the clamping ring30 never completely expands to its unfolded configuration (shown in FIG.1), it is adaptable to irregularly configured neck 54 cross-sections.

For example, if the neck 54 is non-circular in cross-section, thesinusoidally shaped ring 30, in compression, can adapt to the irregularbody passage shape. By making the ring 30 with an uncompressed diameter(D_(K)) greater than the diameter of the body passage (D_(R)) which itis designed to engage, a continuing resilient engagement occurs betweenthe ring 30 and the body passage 36 which may continue even if the bodypassage becomes distended over time. This may occur regularly due tonormally pulsing blood pressure or due to vasodilation over time.

Further by making the diameter of the ring 30 (D_(K)) greater than thediameter of the graft 42 (D_(P)), the graft diameter in use willcorrespond closely to the compressed cross-sectional diameter of thering 30, in position within the body passage 36. This lessens anyunnecessary bunching of the graft 42 around the neck 54.

Turning now to a method for positioning the prosthesis 40 in a desiredlocation within a passage, a retention device 56, shown in FIG. 6, maybe secured to the ring 30 on at least two diametrically opposedorientations so that the device 56 extends generally parallel to theaxis of the prosthesis 40. The devices 56 may include a passage 58 inone end and a bracket 60 which secures the device 56 to the ring 30.Alternatively the passage 58 may be replaced by wire restrainingbrackets (not shown). In some cases barbs 62 may be included on one endof the device 56. However, in many cases, the barbs 62 may beunnecessary.

The device 56 may be engaged by a wire 64 which extends into the passage58 and by a tube 66 which encircles the wire 64, as indicated in FIG. 7.Advantageously, the device 56 and the tube 66 are made of sufficientlyrigid material that pushing against the device 56 by the wire 64 or thetube 66 results in displacement of the prosthesis 40 within the passage36. The wire 64 may have a diameter of about 0.3 to 1 mm.

The prosthesis 40 may be compressed to fit into the tubular catheter 68,for transferring the prosthesis from a remote entry point to the repairsite. The catheter 68 may be inserted into an incision in the femoralartery, for example, and passed to a position within the abdominalaorta, for example, where one may wish to position the annular ring 30.Once in position, the prosthesis 40 may be pushed out of the catheter 68using the tubes 66. Particularly, the tubes 66 are extended inwardlyfrom the exterior of the body by the surgeon while maintaining thecatheter 68 in a fixed position so that the prosthesis 40 is left inposition as the catheter 68 is backed away. If desired, the brackets 60may be made of X-ray opaque material such as platinum, iridium or goldto serve as an X-ray marker.

While the above described procedure for placing the prosthesis 40 may beuseful in some applications, it would be desirable to further facilitateaccurate and controllable placement of the prosthesis 40 in a particularlocation. Once the ring 30 is allowed to expand against the passagewall, re-positioning must be done against the resistant force of thering 30. Thus, it is advantageous to continue to confine the ring 30after the prosthesis 40 leaves the catheter 68, until the prosthesis 40is accurately positioned. To this end, a Bowden tube 70 telescopicallyretains a wire loop 72, as shown in FIGS. 11 and 12. The loop 72 extendsaxially through the tube 70, forms an annular ring 74 and passes througha hole 76 in the proximal free end of the Bowden tube 70. At this point,the looped end 78 of the wire loop 72 receives a blocking wire 80, wherethe loop 78 extends out of the hole 76.

Referring to FIG. 11, the Bowden tube 70 extends along the exterior ofthe prosthesis 40 to a point proximate to the loops 38. The annular ring74 extends around the periphery of the loops 38 at a relatively centrallocation along their length and is engaged in eyelets 82 secured to thering 30. In this way, the blocking wire 80 may be withdrawn axially,releasing the looped end 78 so that the wire loop 72 may be withdrawn,releasing the ring 30 and allowing it to spring open at a desiredlocation. The blocking wire 80 may return, inside the Bowden tube 70, tothe entry point or it may exit the Bowden tube 70 through a gap 71, asshown in FIG. 11.

Referring to FIG. 15, the catheter 68 encircles the prosthesis 40 whichin turn encircles a pair of tubes 66 with wires 64 extending throughthem. If necessary, a guide wire 104 may be included which may be usedinitially to guide the catheter to the desired location and to maintaina path for returning to the same location with additional elements, ifnecessary. The Bowden tube 70 with the looped wires 72 and blocking wire80 also extends inside the catheter 68 between the catheter and theprosthesis 40.

In still another embodiment, a retaining mechanism 84, shown in FIGS. 13and 14, retains the prosthesis 40 in a compressed configuration toaccurately locate it at the desired position within a passage. Themechanism 84 may control a prosthesis 40′ having a pair of rings 30,connected by a graft 42, in a compressed position inside a catheter 68.A guide wire catheter 86 extends axially through the prosthesis 40′. Aplurality of ringlets 88 extend off of the catheter 86. Each of theringlets 88 connects to wire loops 90 which in turn connect to eyelets92 at the free ends of the loops 38.

Referring to FIG. 14, each of the wire loops 90 slidably and releasablyextends through the eyelet 92 and forms a loop end 94. A blocking wire96 extends through the loop ends 94. A portion of each ring 30 along itsfolding axis “B” is wrapped by a wire loop 98 which is engaged on itsfree end by a blocking wire 100. The wire loop 98 may wrap around andover the ring 30, over the outside of the guide wire catheter 86 andinto the interior of the catheter 86 through an opening 102. Each of therings 30 on opposed ends of the graft 42 includes the same parts and maybe operated in the same way.

Thus, to adjust the extent of folding or the proximal-distal height ofthe rings 30 in the orientation shown in FIG. 14, it is simply necessaryto pull outwardly on the wires 98 which may be connected together to asingle wire 103 that extends to the exterior of the patient. To decreasethe height and to decrease the compression of the ring 30, the tensionon the wire loop 98 may be relaxed, allowing the natural spring forcesof the rings 30 to cause the bending of the ring 30 to be relieved andthe ring height to be reduced.

After the catheter 68 is positioned in the desired location, theassembly may be ejected from the catheter using the techniques describedpreviously. The amount of compression of the ring 30 may be adjusted sothat the apparatus 84 can be temporarily positioned at a desiredlocation. If it is determined that the location is not preciselycorrect, the apparatus can be re-compressed, by operating the loops 98,to allow repositioning of the apparatus 84 to a new location. In thisway, it is possible to selectively adjust the position of the prosthesis40′, even after the prosthesis has previously been released to engagethe body passage. If an error is initially made, it is easy toreposition the prosthesis, as necessary. Once the prosthesis is locatedat the desired location, the blocking wires 100 and 96 can simply bepulled out of the assembly through the catheter 68. This allows theprosthesis 40′ to expand, irreversibly. The catheter 86 may be removedthereafter.

If desired, each of the loops 98 can be connected by an independent wireto the exterior of the patient. Or as described previously, the wires 98may be connected so that only one single wire extends outwardly.

Referring now to FIG. 16, illustrating the catheter bundle for theembodiment illustrated in FIGS. 13 and 14 prior to release from thecatheter 68, the catheter 68 encircles the prosthesis 40′. In theinterior of the prosthesis 40′ is the guide wire catheter 86, with oneor more of wires 103 which may be used to control the position of thefolded portion of the annular rings 30. Outside of the guide wirecatheter 86 are a pair of wires corresponding to the blocking wires 96and 100.

In accordance with another embodiment of the invention, the prosthesis40 may be supplemented by one or more additional modules such as theprosthesis 106, shown in FIG. 17. The second prosthesis 106telescopically engages the first prosthesis 40 using an annular ring 30which expands outwardly against the resistance provided by the graft 42.The second prosthesis 106 includes an upper annular ring 30′ and a lowerannular ring 30″. It is the upper annular ring 30′ which engages thegraft 42 while the lower annular ring 30″ engages in the distal neck 54b. Because the amount of telescopic extension of the second prosthesis106 into the first prosthesis 40 may be adjusted, a wide arrangement ofdifferent vessel longitudinal sizes can be accommodated.

The prosthesis 106 including a pair of rings 30′ and 30″ may have alongitudinal torsion preventing wire 31 as shown in FIG. 23. The wire 31may be wrapped around the rings 30′ and 30″ to control torsion ortwisting of the prosthesis 106 about its longitudinal axis and toprovide additional longitudinal support. The wire 31 is covered by thegraft 42, either by positioning the wire 31 in the interior of theprosthesis 106 or by weaving the wire 31 through a graft 42 made offabric. If desired, one or more additional wires 31 may be providedaround the circumference of the rings 30′ and 30″.

The second prosthesis 106 may be located inside the first prosthesisusing the guide wire 104 which stays in position after all of the wiresutilized to position the first prosthesis have been removed. Thereafterthe second prosthesis 106 may be run back to the same location using theguide wire 104 which stayed in place after the first prosthesis 40 waspositioned.

The guide wire 104 maintains the opening of the graft as well. However,in practice the blood flow through the prosthesis 40 causes it to actlike an open, expanded, windsock. Therefore, using the guiding action ofthe guide wire 104, the second prosthesis 106 can engage the interiorsurface of the graft 42. Thus, the combination of the two prostheses 40and 106 can adjustably span between the necks 54 a and 54 b by alteringthe extension of the prosthesis 106 into the prosthesis 40.

The prostheses 40 and 106 may also be positioned using the mechanism 84,as shown in FIG. 22. The prosthesis 106 may be inserted into thepatient, already located within the prosthesis 40, using an additionalset of blocking wires 96′. The blocking wires 96′ extend through thelower loops 94 and through the interior of the prosthesis 40. In thisway, the prosthesis 106 may be manipulated independently, adjustablytelescoping within the prosthesis 40. In this case, the wires 98 and 98′may run separately to the exterior of the patient to facilitateindependent manipulation of the prostheses 40 and 106.

A prosthesis similar to those described above may also be used toprovide a bifurcated stent 120, shown in FIG. 18, which extends from theabdominal aorta 48 and its associated neck 54 a past the lower neck 54 band into the iliac or pelvic arteries 108 and 110. Again, a prosthesis40 as described above is provided for engagement with the neck 54 a.Instead of the prosthesis 106 described previously, a speciallyconfigured prosthesis 112 may be utilized next. The prosthesis 112,shown in FIG. 19, may include a ring 30′ on its upper end and a pair ofrings 114 on its lower end. The rings 114 need not be compressed sincethey simply maintain the lower end of the prosthesis 112 in an openconfiguration.

As shown in FIGS. 20 and 21, the upper end of the prosthesis 112 mayhave a circular configuration of the type described previously. Thelower end may have a double tubular configuration including a pair ofpassages 116 defined by a connection 118 which extends axially along theprosthesis 112 to form two separate chambers 116 terminated by the rings114. The rings 114 may be oriented at an angle to the axis of theprosthesis 112 to allow easy entrance from the iliac arteries 108 and110.

A pair of smaller diameter prostheses 120 are bilaterally insertedthrough each iliac artery 108 or 110 for engagement with the prosthesis112. Particularly, the upper rings 30″ enter through rings 114 and passinto the interior of the passages 116 where they expand outwardlyagainst the graft 42. At the same time the other end 122 of eachprosthesis 120 engages the neck 54 b at the iliac artery 108 or 110. Oneof the prostheses 120 may be inserted using the same guide wire utilizedto position the previously positioned prostheses. However, the otherprosthesis 120 must be positioned independently of that guide wire. Forthis purpose, x-ray proof materials may be utilized on the rings 30″ and114 to facilitate location of the rings 114 and passage through them bythe prosthesis 120 which is inserted without the previously locatedguide wire.

With the apparatus and techniques described above, it should be apparentthat the prostheses 40, 40′, 120 may be positioned without substantiallyblocking the flow of blood even during the surgical procedure. Moreover,the prostheses 40, 40′ or 120 are configured so as not to substantiallyinterfere with intersecting vessels such as the renal arteries. At thesame time a modular approach may be utilized to adjust for differentphysiologies. This in combination with the fact that the annular ring 30need never extend to its fully undeformed configuration, means that itis not necessary to stock a variety of different stents. Instead it ispossible to have a relatively limited or even a single set of sizeswhich can be adapted to a variety of patient conditions.

Because of the fact that the rings 30 have a C-shaped configuration inposition in the body passage, it is possible to locate the prosthesis ina relatively narrow neck 54 region. Since the ring 30 remains in itscompressed configuration in use, it adapts for short term and long termdistension of the treated passage. Moreover, because of the constantlyapplied spring bias pressure of the rings 30, good sealing contact ismaintained between the rings 30 (and the prostheses) and the wall ofbody passage even if the passage is irregularly shaped.

With the positioning techniques described above it is possible toaccurately position the prosthesis as desired within a body passage.This is because the prosthesis is maintained in a first compressedconfiguration as it is loaded and transported to the desired location sothat it may be positioned without having to overcome friction betweenthe prosthesis and the vessel passage. Once in its desired position, theprosthesis can be activated to engage the wall. It is also possible toreposition the prosthesis after the wall has been engaged if desired.This facilitates accurate positioning and avoids the need to attempt toreposition the prosthesis after it has irreversibly assumed the expandedconfiguration. In this way the surgeon has considerable control (throughthe guide wire and tubes, for example) to accurately position aprosthesis at its most effective position.

The prosthesis 40 may also be utilized to replace a diseased portion ofthe ascending aorta as indicated in FIG. 24. An annular ring 30 may bepositioned in the remaining portion of the ascending aorta “D” after aportion of the aorta has been surgically removed. The clamping ring 30secures itself to the inside surface of the aorta “D” as describedpreviously. The clamping ring is connected to a tubular, flexible sleeveor graft 42 and the graft 42 in turn connects to a sewing ring 130 whichfacilitates connection to a mechanical heart valve 132. The details ofthe valve and the graft will be known to those of skill in the art andare described in U.S. Pat. No. 5,123,919, issued to Sauter et al., whichis hereby expressly incorporated by reference herein.

The graft 42 may be any of a variety of lengths depending on the amountof tissue involved. The graft 42 could extend further than isillustrated and may be considerably shorter. For example, where it isonly necessary to replace the heart valve, the graft 42 may amount tolittle more than a short flexible sleeve connecting the mechanical valve132 to the ring 30.

While the present invention has been described with respect to a limitednumber of preferred embodiments, those skilled in the art willappreciate numerous modifications and variations therefrom. For example,while the device has been described in some instances as a vascularstent for treating aneurysms, the invention may be applicable tosecuring any device to an internal passage. In addition, it should beappreciated that certain embodiments of the present invention may haveonly one or more of the advantages described above or may instead haveother advantages not specifically mentioned herein. It is intended thatthe appended claims cover all such modifications and variations as fallwithin the true spirit and scope of the appended claims.

1. A prosthetic device comprising a prosthetic heart valve, a flexibletubular sleeve having a first end connectable to said valve and a secondend, and a deformable, resilient annular ring connected to said secondend and arranged to connect said device to the interior surface of aportion of the ascending aorta, said ring comprising windings formed ofa strand of wire, said windings wrapped one over the other and onearound the other to form a bundle of windings that are connectedtogether, the diameter of said bundle of windings corresponding with thediameter of said ring.
 2. The prosthetic device according to claim 1wherein a rigid member longitudinally connects to said annular element,said member being less flexible than said graft.
 3. The prostheticdevice according to claim 2 wherein said member is a wire.
 4. Aprosthetic device comprising a first prosthesis having an annular,resilient element and a bifurcated graft, said annular elementcomprising windings formed of a strand of wire, said windings wrappedone over the other and one around the other to form a bundle of windingsthat are connected together, the diameter of said bundle of windingscorresponding with the diameter of said annular element, said bifurcatedgraft including a first tubular section and a pair of tubular sectionsintegrated with said first tubular section and at least a free end, saidannular element located at said free end and coaxial with saidbifurcated graft, said first tubular section connected to said annularelement and each of said pair of tubular sections has no annularelement.
 5. The prosthetic device according to claim 4, furthercomprising a second prosthesis and a third prosthesis respectivelyengaging with said pair of tubular sections of said first prosthesis. 6.The prosthetic device according to claim 5, further comprising a fourthprosthesis engaging with said first tubular section of said firstprosthesis.
 7. The prosthetic device according to claim 6 wherein saidfourth prosthesis has a pair of annular resilient deformable elementsand a tubular graft, said annular elements of said fourth prosthesisbeing attached to free ends of said tubular graft, one of said annularelements of said fourth prosthesis adapted to engage with the interiorof said first prosthesis.
 8. The prosthetic device according to claim 5wherein said second and third prosthesis each includes a pair of annularresilient deformable elements and a tubular graft, one annular elementof said second and third prosthesis attached to a free end of arespective tubular graft and adapted to engage with the interior of saidfirst prosthesis.
 9. The prosthetic device according to claim 8 whereinsaid annular resilient deformable elements of said second and thirdprosthesis are a ring comprising a bundle of concentric windings formedof a strand of wire.